Monday, June 17, 2013

Worms in Fish (Video)

I first wrote about fish parasites 7 years ago (part 1, part 2), and hundreds of comments poured in ranging in their content from incredulity to oaths of never eating fish again. That made me sad. So before you swear off fish, I'd like to ask whether you go on hikes or nature walks on the East coast of the US? What does that have to do with fish? Let me explain.

Ticks are a very common problem in this part of the country and they spread lyme disease. Hopefully, you find the tick, remove it correctly, and get a course of antibiotics. But if you don't notice the tick, you could get lyme disease. In an effort to compare whether fish worms or ticks are more harmful to human health, I looked up statistics for lyme disease in Massachusetts and anisakiasis (gastrointestinal disease caused by fish parasites) in Japan. Why Japan? Because the incidence of anisakiasis in the US is so puny, it's laughable. Japan on the other hand consumes an incredible amount of raw fish and has the highest rate of anisakiasis of anywhere in the world at the whopping 1,000 cases per year [1]! How many cases of lyme disease do we have in MA? In 2011, we had 1,800 cases and that's not bad, because in 2009, we had 4,000+ cases [2]. Population of Japan is 127.8 million. Population of Massachusetts is 6.6 million. If we do a bit of math (using the smaller 1,800 cases of lyme disease), we get that lyme disease is 35 times more likely in Massachusetts than anisakiasis is in Japan and that's on a good year.

The point of this argument is not to stop you from hiking, it's to explain that the risk of getting sick from a fish worm is way smaller than many other risks you are probably already taking in life.

If you find fish parasites really icky, here are some fish in which parasites are practically non-existent:

Anything farm-raised except for salmon

Tuna

Here is a list of fish that could in theory have parasites, but they are extremely rare:

Another great video! As a fishmonger, I thank you for sharing the tips :) What are your thoughts on curing fresh wild salmon (never frozen)? I always recommend against it, especially since we sell some wonderful Scottish Atlantic. But really, the risks are probably pretty low of parasitic infection.

I would recommend very strongly against curing wild salmon that is not previously frozen. Parasites can survive the curing process and wild salmon is very prone to tapeworm that is not visible on the fish. I am very good at spotting cod worms and anisakis, but even I would worry about tapeworm. If someone really wants to work with wild salmon for curing, I'd recommend using king salmon (chinook) and freezing it for 7 days first. King salmon has a very high fat content and freezes fine, but coho and sockeye have a low fat content and don't freeze well. To tell you the truth, I don't think they taste great either, so I don't think they are worth working with with or without freezing.

Do you know if smelt roe purchased from a japanese market would be safe? I don't know if they previously froze it or not. I also wasn't able to find if worms are found in roe and whether they are common in smelt or not. It says it is wild from iceland.

Yes, smelts can have parasites. Don't know whether roe has less chance than meat itself. From my experience with Japanese markets, almost everything they sell is previously frozen. But you should ask them.